black tea

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Related to English Tea: afternoon tea

black tea

(blak tee) ,

Camellia sinensis

(trade name),

English tea

(trade name),

Theaflavin

(trade name)

Classification

Therapeutic: central nervous system stimulants
Mental alertness HeadacheWeight lossMyocardial infarction and atherosclerosis prevention

Action

Black tea contains caffeine (2–4%) a methylxanthine that stimulates the CNS through adenosine receptor blockade and phosphodiesterase inhibition, relaxes smooth muscle in the airways, stimulates the heart and has diuretic effects. Theaflavins and tannins present in black tea are responsible for antioxidant properties.

Therapeutic effects

CNS stimulation.
Diuresis.
Elevated heart rate and BP.

Pharmacokinetics

Absorption: Unknown.
Distribution: Unknown.
Metabolism and Excretion: Unknown.
Half-life: Unknown.

Time/action profile

ROUTEONSETPEAKDURATION
POunknownunknownunknown

Contraindications/Precautions

Contraindicated in: Allergy or hypersensitivity to caffeine or tannin; Obstetric: Pregnancy and lactation (in high doses due to caffeine content).
Use Cautiously in: Cardiac arrhythmias; Diabetes; Peptic ulcer disease; Osteoporosis (caffeine increases urinary calcium excretion); Iron deficiency anemia (may worsen); Pediatric: Safety and efficacy has not been established in children.

Adverse Reactions/Side Effects

Cardiovascular

  • arrhythmia
  • hypertension
  • tachycardia

Central nervous system

  • insomnia
  • tremor

Dermatologic

  • rash
  • hives

Endocrinologic

  • hyperglycemia

Fluid and Electrolyte

  • hypokalemia
  • hyponatremia

Gastrointestinal

  • constipation
  • increased stomach acid

Hematologic

  • iron deficiency
  • microcytic anemia

Genitourinary

  • diuresis
  • increased urine sodium, potassium, and calcium levels

Musculoskeletal

  • rhabdomyolysis (high doses)

Interactions

Cimetidine, disulfiram, fluvoxamine, phenylpropanolamine, fluoroquinolones, and estrogens can ↓ caffeine clearance and ↑ adverse effects. Caffeine can inhibit dipyridamole -induced vasodilation.Abrupt withdrawal of caffeine can ↑ lithium levels.Additive stimulatory effects with CNS stimulants.Caffeine can ↑ theophylline levels.May ↑ heart rate and BP when used with bitter orange.May ↑ stimulatory effects when taken with ephedra and green tea.
Oral (Adults) Heart disease prevention—1–4 cups daily; Headache/mental performance—1–5 cups daily. One cup of black tea contains approximately 50 mg caffeine. A maximum of 8 cups/day has been suggested.

Availability

Tea leaves: OTC

Nursing implications

Nursing assessment

  • Assess BP and heart rate periodically in patients at risk for cardiovascular side effects.
  • Lab Test Considerations: Monitor liver and kidney function tests and blood glucose, plasma homocysteine, and uric acid levels periodically in patients with who drink large amounts of black tea.

Potential Nursing Diagnoses

Acute pain (Indications)

Implementation

  • Drink tea as desired.

Patient/Family Teaching

  • Advise patient that chronic use of black tea may be habit-forming. Abrupt discontinuation may lead to withdrawal symptoms; decrease gradually.

Evaluation/Desired Outcomes

  • Increased mental alertness.
  • Increased urine output.
  • Decrease in headache pain.
Drug Guide, © 2015 Farlex and Partners

black tea

Tea made from leaves that have been fermented before they are dried.
See also: tea
Medical Dictionary, © 2009 Farlex and Partners
References in periodicals archive ?
English Tea Shop is using a 1 [pounds sterling] million invoice finance package and a 450,000 [pounds sterling] trade limit from HSBC to increase its importing capabilities, which it hopes will also increase turnover by about 20 percent in 2018.
"We have set some ambitious goals [for ourselves] for the next few years, including expanding our global reach and continuing to grow as a truly sustainable business, both of which HSBC has been instrumental in supporting," said Suranga Herath, chief executive at English Tea Shop.
For those who enjoy tea, the Restaurant brings to you a lavish presentation of traditional English tea along with an exquisite selection of loose tea from "L'art du the".
Coventry-based New English Teas is now exporting its range of high value gift packed teas and associated giftware to Russia.
In spring 2007, New English Teas joined UK Trade & Investment's flagship Passport programme, which gives new exporters the training, planning and ongoing support they need to succeed overseas, and recently completed the scheme.
"UK Trade & Investment also helped us source finance from the European Regional Development Fund to develop translations and packaging for overseas markets, which has been a big help, especially for a small company like ours." International trade adviser Brian Mountford, based at Coventry and Warwickshire Chamber of Commerce, said: "It has been a pleasure to help New English Teas to develop its export sales.
"Our international trade adviser, Brian Mountford, has been a great sounding board for our ideas and helped us look at new avenues to explore." Mr Mountford, who is based at Coventry and Warwickshire Chamber of Commerce, said: "It has been a pleasure to help New English Teas to develop its export sales."
New English Teas supplies fine teas to independent retailers throughout the world and has moved to the city from Somerset after being bought by local businessman Nick Houghton.
Serving up new business are (from left) Richard Thomas of Cimbali, Pat Moroney of Deeley Properties and Nick Houghton of New English Teas.
English Teas, recently expanded its range of boxed organic teas.
The Spitfire Centre, which was finished by Coventry firm Deeley Properties earlier this year, is the new home of fine teas suppliers New English Teas, who have moved to the city from Somerset after being bought by local businessman Nick Houghton.
The company has recently expanded its range of Harrisons & Crosfield English teas to include a comprehensive range of organic teas.

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